Atomizer and method for disseminating toxicants



Nov. 14, 1967 SPRAGG ET AL 3,352,238

ATOMIZER AND METHOD FOR DISSEMINATING TOXICANTS Filed Oct. 12, 1965 2Sheets-Sheet 1 INVENTORS R. SPRAGG, ER Av PRICE 5 M. WOOLD'RIDGEATTORNEYS NOV. 14, 1967 SPRAGG ET AL 3,352,238

ATOMIZER AND METHOD FOR DISSEMINATING TOXICANTS Filed Oct. 12, 1965 2Sheets-Sheet 2 INVENTORS HAL R. SPRAGG, LUTHER A. PRICE, JAMES M.WOOLDRIDGE ATTORNEYS United States Patent 3,352,238 ATUMEZER AND METHODFOR DISSEMINATING TOXICANTS Hal R. Spragg and Luther A. Price, Phoenix,and James M. Wooldridge, Glendale, Ariz., assignors to Universal MatchCorporation, a corporation of Delaware Filed Oct. 12, 1965, Ser. No.495,255 8 Claims. (Cl. 102-39) ABSTRACT OF THE DISCLOSURE A pyrotechnicatomizer for normally solid toxicant charges which includes a propellantcharge and in which the size of the propellant charge and the atomizergeometry are adapted to provide a relatively high-velocity stream ofpropellant gases. The propellant gases flow through pilot apertures inthe charge and disseminate the toxicant by abrasion of the charge underlimited heat-exchange conditions, thereby avoiding vaporization ormelting of a substantial part of the toxicant charge.

This invention relates to the dissemination of toxicant agents. In aparticular aspect, the invention concerns a novel method ofdisseminating toxicants and, in another aspect, concerns apparatus forpracticing such methods. In a further aspect, the invention particularlyconcerns the dissemination of toxicants having relatively lowheatdecornposition temperatures and methods and apparatus for carryingout the dissemination of such toxicants.

As used herein, the term toxicant is intended to mean and encompass awide variety of biologically active agents including the so-calledeconomic poisons such as insecticides, fungicides, herbicides and thelike, as well as the various irritants and toxicants employed in policeand military operations such as so-called tear gases, and war gases,both the non-lethal debilitating agents and the lethal agents such asnerve gases and the like. Of particular interest in connection with theinvention are those toxicants having a relatively low heat-decompositiontemperature, i.e., substantially below the temperature of gases producedpyrotechnically in the devices and the methods of the prior art.

In the dissemination of toxicants, it is generally required that thetoxicant be disseminated in the locus to be treated during a suitablyshort time period in order to establish the minimum effectiveconcentration of the toxicant in the locus before dispersion eifectscome into operation. Additionally, it is required that the bulk of thetoxicant be disseminated in a biologically active form, avoidingdecomposition of the agent into a less effective or totally ineffectiveform. Also, practical considerations such as the mobility, cost andreliability of the disseminating apparatus, particularly as influencedby military or police requirements, make it highly desirable that theoverall unit weight efiiciency of apparatus used in the dissemination oftoxicants be as high as possible. The term overall unit weightefficiency used herein means the percentage relationship of the weightof toxicant actually and effectively disseminated to the total weight oftoxicants and associated disseminating hardware, propellants, found inthe original disseminating apparatus. The classical overall unit weight3,352,238 Patented Nov. 14, 1967 efiiciency of the prior art pyrotechnictoxicant disseminators is in the range 10-20 percent, although higherefiiciencies have long been a prime desideratum.

It is an object of the present invention to provide a novel method fordisseminating toxicants, particularly those toxicants having arelatively low heat decomposition temperature;

Another object of the invention is the provision of a simple andrelatively inexpensive, yet highly effective atomizing device fortoXicant-s providing quick dissemination of the toxicant into the locusto be treated;

Another object of the invention is the provision of an atomizing devicefor toxicants having a relatively much higher overall unit weightefficiency than those found in the prior art;

Yet another object of the invention is the provision of an atomizingdevice having a high overall unit weight efliciency which is especiallyadapted to the dissemination of toxicants having relatively low heatdecomposition temperatures;

Another object of the invention is the provision of a method ofdissemination of toxicants and apparatus useful in the practice of suchmethods whereby the toXicant is pyrotechnically disseminated by meansother than simple vaporization which often causes thermal degradation ofa substantial quantity of the toxicant.

Yet another object of the invention is the provision of a pyrotechnicatomizing device for toxicants wherein the pyrotechnic and t-oxicantcharges are maintained until actual operation of the device in a sealedintegument, thereby minimizing the danger of inadvertent contaminationof the surroundings by the toxicant and further minimizing thepossibility that the contents will become damaged by external causes.

Other, further and more specific objects of the invention will becomereadily apparent to persons skilled in the art from a consideration ofthe following description when taken in conjunction with the drawingsand examples wherein specifically preferred embodiments of the inventionare shown and exemplified.

FIG. 1 is an external perspective view of a presently preferredembodiment of my invention chosen for purposes of illustration;

FIG. 2 is a cross-sectional view of the device of FIG. 1 taken alongsection line 22 of FIG. 1;

FIG. 3 is an end-view of the device of FIG, 1 taken along section line33, the view being partially broken away to show the detail of the fuseassembly;

FIG. 4 is a partial sectional view of the gas-distrubting orifice plateof the device of FIGS. 1-3;

FIG. 5 is a partial sectional perspective view of a gaspermeabletoxicant charge element adapted for use in the assembly of FIGS. 1-3

FIG. 6 is a perspective view of the retaining ring which secures thefuse-ignitor assembly of the device of FIGS. 1-3;

FIG. 7 is a perspective view of flame-front-limiting partition screenfor use in the device of FIGS. 1-3;

FIG. 8 shows another embodiment of the invention wherein the toxicantcharge elements are of a generally elongate cylindrical shape and arepositioned in the toxicant chamber of the device as a gas-permeablebundle;

FIG. 9 shows a single cylindrical toxicant charge element of the deviceof FIG. 8.

In the practice of my invention, a normally solid toxicant compositionis disseminated by contacting the composition in an atomizing zone witha stream of carrier gas under gas velocity conditions providing abradingcontact between the gas and the composition, thereby to produce anaerosol of the toxicant composition in the carrier gas. In the presentlypreferred embodiments, the carrier gas is pyrotechnically produced andthe toxicant composition is contacted with the relatively high velocitystream of hot pyrotechnically produced gases, the How path of the gasesbeing limited to provide abrading, limited heat exchange conditions ofpressure, velocity and contact time, thereby producing the aerosol ofthe toxicant in the pyrotechnically produced carrier gas withoutdegrading a substantial portion of the toxicant material. Manifestly,the methods of the invention are advantageously employed in connectionwith the dissemination of toxicants having a relatively low thermaldecomposition temperature. The pyrotechnic gases are produced by firinga propellant charge in a gas-generating zone, the flame front thusproduced being physically segregated from the toxicant charge, suitablyby means of a flamefront-limiting screen or other equivalent means. Thepath of expansion of the hot propellant gases produced in thegas-generating zone is limited to provide a relatively high velocitystream which is directed through a toxicant charge which isgas-permeably disposed in an atomizing zone. By suitable selection ofconditions of pressure velocity and contact time, the contact betweenthe propellant gas and the toxicant charge can be adjusted to provideabrading but limited heat-exchange conditions. Thus, the toxicant isaerosolized in the carrier gases without raising the temperature of asubstantial portion of the toxicant to its decomposition temperature.

According to another aspect of the invention, 1 provide apparatusespecially adapted to disseminate toxicants according to the methodshereabove disclosed. Briefly, the apparatus comprises a pyrotechnicgas-generating propellant charge, a toxicant charge and a casingenclosing said charges. The casing is divided by a fiame-front-limitingpartition into a gas-generating chamber containing the propellant chargeand an atomizing chamber containing the toxicant charge. The toxicantcharge is positioned within the atomizing chamber in the path of gasesgenerated by firing the propellant charge. The casing and the propellantand toxicant charges are dimensioned to provide abrading, limited heatexchange contact between the propellant gas and the toxicant when thepropellant is fired, thereby to aerosolize the toxicant without raisingthe temperature of a substantial portion thereof to its decompositiontemperature.

Turning now to the drawings inw hich presently preferred embodiments ofthe apparatus of the invention are depicted for purposes ofillustration, FIG. 1 is an external perspective view of such deviceshowing the generally elongate casing 1 which encloses the propellantand toxicant charges. The igniting assembly comprises a fuse 2 whichignites an initiating charge secured to the casing by means of a foilcover 3 and a retaining strap 4. Upon the ignition of the propellantcharge, the aerosolized toxicant issues from the discharge end of thecasing, generally indicated by the reference numeral 5, through a screenassembly 6.

FIG. 2 is a cross-sectional view of the device of FIG. 1. The casing 1is constructed of relatively thin, lightweight metal or other suitablematerials such as plastics, cardboard and the like. The propellantcharge 11 is positioned in a closed end of the casing, the closure beingeffected by crimping the end of the casing (indicated by referencenumeral 12) over a disc-shaped end member 13' thereby to provide asubstantially gas-tight closure. The ignitor charge 14 is disposedagainst the exterior of the end member 13, within the cavity formed bythe crimped end of the tubing and the end member. A springloaded clip15, spot welded to the end member 13, holds the fuse 2 in position tofire the igniting charge 14. When the igniting charge 14 is fired, theend member 13 is heated thereby and, in turn, the heated end member 13ignites the main propellant charge 11. This so-called through bulkheadignition, while not necessary to the operation of the apparatus of theinvention, is convenient and advantageous in that it permits the mainpropellant charge to be completely enclosed by a gastight casing andobviates providing holes in the casing to permit the insertion ofignition wires or fuses, The igniting charge 14 and the fuse 2 aresecured to the casing and positioned in heat-exchange relation with themain propellant charge by means of the foil cover 3 and the retainingstrap 4 which encircles the casing below the shoulder formed by thecrimped end of the casing 12. The propellant charge 11 is physicallysegregated from the toxicant charge elements 16 by means of screens 17which divide the easing into a gas-generating zone containing thepropellant charge 11 and an atomizing zone containing the toxicantcharges 16. The screens 17 limit the flame front produced by thepropellant charge 11 and direct the gaseous products of the combustionof the propellant charge through the charge elements 16. These chargeelements are separated by screens 18 which assist in positioning thetoxicant charge elements in gas-permeable relation to the propellantgases flowing therethrough. The pressure within the casing duringoperation of the device is maintained and controlled by means of anorifice and distributing plate 19 positioned and retained in thedischarge end of the casing by means of the cap member 20. Prior tofiring, the contents of the casing are protected by a seal 20a ofsuitable membrane-like plastic or equivalent material which ruptures orreleases when the device is fired, thereby permitting dissemination ofthe toxicant aerosol into the locus of the device.

FIG. 3 is a partially broken away end view of the device of FIG. 1showing the crimped end of the casing, the fuse 2, the fuse retainingclip 15 and the foil cover 3.

FIG. 4 shows a suitable pressure-regulating and gasdistributing orificeplate for use in the device of FIG. 1. The general direction of the gasflow through the orifice plate is shown by the arrow 41. The plate isdrilled as shown to provide radial ducts 42 communicating between therelatively large central aperture 43 and the periphery of the orificeplate. A series of longitudinal ducts 44 are drilled in the upstreamside of the plate. These longitudinal ducts communicate with the radialducts 42. The orifice plate, drilled as shown in FIG. 4, provides foreven distribution of the gas flow across the cross-sectional area of thecasing.

FIG. 5 is a partial sectional view of the gas-permeable charge elementsshown in cross-section in FIG. 2. These charge elements are generallycylindrically shaped and provided with a plurality of longitudinal pilotholes 51 through which the propellant gases pass when the device isfired. Of course, as the toxicant charge is abraded, the holes aregradually enlarged until essentially the entire charge element has beendisseminated.

FIG. 6 is a detailed view of the retaining strap which secures andpositions the foil and fuse on the normally closed end of the casing.The strap is generally circular as shown and is provided with a recessedportion 61 which receives the fuse when the strap is mounted upon thecasing of the device of FIG. 1. The strap is secured by means of a tab62 which engages the slot 63 and is then bent backwardly as shown inFIG. 1.

A variety of toxicant charge shapes are possible, the principalrequirement being gas permeability when positioned in the atomizingchamber. For example, as shown in FIG. 9, the solid toxicant charges canbe shaped as elongate cylinders 81 which can be packed in a generallycylindrical bundle for placement in the atomizing chamher.

In the dissemination of toxicants having relatively low thermaldecomposition temperatures in accordance with the invention, it isnecessary to adjust the pressure-temperature-contact time conditions inthe atomizing zone to provide abrading, limited heat-exhange conditions.The term limited heat exchange, as used herein, is intended to depictconditions whereby substantially all of the toxicant charge isdisseminated by the formation of an aerosol through incipient meltingand abrasion of the solid charge by the relatively high velocity carriergas stream passing through the atomizing zone. It is believed that theminor portion of the toxicant charge which is actually vaporized by thehot gases provides a transient thermal insulation for the bulk of thetoxicant charge according to the well-known leydenfrost shieldingphenomenon.

second. It is possible to employ somewhat higher gas velocities (andcorrespondingly shorter contact times) but this generally requiresincreased internal pressure, making it necessary to employ heaviercasing material. Lower gas velocities (and correspondingly longercontact times) will be only partially eflective, especially when thetoxicant is easily thermally degraded.

Among the toxicants which can be successfully disseminated in accordancewith the methods and apparatus herein disclosed may be mentioned CS, CN,DM, HD (mustard gas), Sarin, Tabun, and other organophosphorus orsimilar compounds including structurally related compounds. In addition,it is feasible to disseminate insecticides such as DDT, TEPP andChlordane as well as The present invention contemplates the use ofpressures various dye stuffs for the production of smokes such as in theatomization zone which are notably low, e.g.,1-methylaminoanthraquinone; 1,4-diamino-2,3 dihydro- 5-100 p.s.i.,especially about -50 p.s.i. The pressure anthraquinone;1,9-benz-l0-anthr0ne; 1,4-di toluidinowithin the devices of theinvention can be suitably conanthraquinone and HC. Transcinnamic acidand 2,4-dihytrolled by the adjustment of the number, placement anddroxybenzophenone, compounds which have very low size of the ducts andapertures in the orifice plate as 20 thermal decomposition temperat havebeen successshown in the drawings. fully disseminated by the devices andmethods herein dis- The temperature conditions encountered in theatomizclosed even though propellants with flame temperatures ing zonecan be controlled by the selection of a propellant as high as 3000 K.were employed. Toxicants such as having a suitable burning temperature.The prime re- Tabun and HD (mustard gas) also have relatively lowquirement of the propellant is that it provide suflicient decompositiontemperatures (130 C. and 150180 0., thermal and kinetic energy todisseminate the toxicant. respectively). Toxicants such as DM and CN aretable However, it is also desired that the mildest possible temup totheir boiling points (410 C. and 245 C., respecperature conditions bemaintained in the atomizing zone. y)-

To this end, it is generally desired to select a propellant n general,the ratio of the weight of propellant to having the highest possibleflame temperature, gas release Weight of toxicant employed according tothe invention and burning rate characteristics consistent withmaintainill vary from about 0.5 to about 5, depending on the ingsuitably low temperature conditions in the atomizing specific toXicantcompounds and propellants involved. Of zone to prevent thermaldegradation of the particular Course, propellant must be selected hichWill provide toxicant material. As representative of the various typesof Combustion Products Which are Chemically Compatible propellants whichmay be employed to disseminate vari- With the toxicant compound. oustoxicants may be mentioned the so-called cool According to anotherembodiment of the invention, a b i ll t h as th various ammoniumiblowing agent is incorporated in the toxicant charge eletratecompositions, guanidine nitrate propellants, the so- Ineht to Promotethe abrasion y the stream f Carrier called mono propellants such ashydrazine nitro A typieal blowing agent which is successfully emmethane,lower alkyl nitrates, H 0 and the like, and P y in this manner is ,7tetra-azobigasless heat sources such as thermite-type compositions in Yl 21 a ion conjunction with volatile diluents such as water, etc. These0f the toxicant Charge is also Promoted y P g a cool burning propellantsgenerally produce flame temstream of abrading carrier gas containingsolid particles. peratures of not greater than about 2000 K. On the Forexample, such carrier gases may be produced by other hand, depending onthe particular toxicant to be burning a metal fuel-oxidizer mix in thepropellant chamdisseminated, it is possible to employ a propellanthaving her such as an aluminum-potassium perchlorate mix r a somewhathigher flame temperature, such as the single a mix comprising a doublebase propellant of the RDX- B (flame temperathfe 30000 K'): the so-eahedtype and a finely divided silica such as that commercially double ba sepropellantshavmg a flame temperature of avaiiabie under the tradename2200*2800 composlte PEOPeHantS, In another embodiment of the invention,a liquid tox- (fiame temperature 19003500 K.), RDX-type propelicant canbe dis ensedb b1 .4 lants (flame temperature 2500-3000" K.) RDX double Pmg 1 ."f a 5mm 6 form for pos1t1on1n within the atomizm chamber s basepropellants (flame temperature 3300 K.). h D a m h device f theinvention and the area t e case of a normally SOlld toxicant. Th s canbe accomcasmg of t e pllshed by distributing the liquid toxicant througha available for gas flow through the gas-permeable toxicant Orous Waferf the i fi h FI charge elements should be sized to provide contact times2 o genera gun} Ion S own In between the carrier gas and the toxicantcharge elements or by encapsulatmg hqmd. toxlcanl and the]? mix- Whichare sufliciently short to minimize the thermal dethe lncapsualtedtoxlcant with a s,u1tab1e Sohd composition of the toxicant duringformation of the tenal whlch can be than Shaped as deslredaerosol. Forexample, it has been found that calculated 6O EXAMPLE gas velocities inthe range of from about to about 100 feet per second at the dischargeend of the disseminating To demonstrate the principles of the invention,several device of the drawings will produce satisfactory results.devices of the configuration Shown ill FIGS- 0f the Velocities in thisrange provide calculated contact times drawings Were assembled andtested With the s l s in the atomizing zone in the order of a fractionof a shown in Table 1 below. In each test the casing was fab- TABLE IPropellant Toxicant Overall Unit Test Weight T p Weight, g. Type Weight,g. Percent RDXdouble base 12.7 O 16.6 30 SR4990 30.1 C8 67.7 34 SR 499030.2 l-methylamino 54.7 29

anthraquinone.

ricated of .026 mm. thick steel tubing having an internal diameter of 24mm. The propellants were selected to provide a gas velocity through theatomizing zone in the range of 60 100 f.p.s. which was calculated fromthe volumetric gas yield of the propellant, the burning rate and theopen cross-sectional area of the orifice plate. Exit gas temperaturesranged from ISO-300 C. The orifice plates were drilled to provide aninternal gas pressure of from 2050 p.s.i. So-called hot burningpropellants were deliberately selected in order to demonstrate thattoxicants having low heat decomposition temperatures could neverthelessbe effectively disseminated by proper adjustment of contact time,pressure and gas velocity conditions to provide abrading, limited heatexchange conditions in the atomizing zone.

The aerosols thus produced were collected in an absorption column.Infrared analysis for structure and ultraviolet and spectrophotometricanalyses for quantities confirmed that there was no substantial thermaldegradation of the toxicant charge during dissemination.

My invention has been described particularly with reference to thepresently preferred embodiment thereof chosen for purposes ofillustration. However, it is not intended to indicate that the scope ofthe invention is limited to the particularly preferred embodiments shownand described but, rather, only by a just interpretation of thefollowing claims.

I claim:

1. A pyrotechnic atomizer for toxicants comprising: a pyrotechnicgas-generating propellant charge; a normally solid toxicant chargeelement having longitudinal pilot apertures therein, providing aninitial conduit for propellant gases flowing therethrough, whichapertures are enlarged by abrasion of the charge element by said gasesuntil essentially the entire charge element is consumed; a casing forsaid propellant and toxicant charges; a flamefront-limiting partitiondividing said easing into a gasgenerating chamber containing saidpropellant charge and an atomizing chamber containing said toxicantcharge positioned therewithin to provide abrading, limited heatexchangecontact between the propellant gas and the normally solid toxicantcharge element to aerosolize said toxicant charge when said propellantis fired without raising the temperature of a substantial portion ofsaid toxicant to its decomposition temperature.

2. A pyrotechnic atomizer especially adapted to aerosolize a toxicanthaving a relatively low decomposition temperature comprising: apyrotechnic gas-generating propellant charge; a normally solid toxicantcharge element having longitudinal pilot apertures therein, providing aninitial conduit for propellant gases flowing therethrough, whichapertures are enlarged by abrasion of the charge element by said gasesuntil essentially the entire charge element is consumed; a generallyelongate casing for said propellant and toxicant charges; afiamefrontlimiting partition screen dividing said easing into agasgenerating chamber containing said propellant charge and an atomizingchamber containing said toxicant charge gas-permeably positionedtherewithin to provide abrading, limited heat-exchange contact betweenthe propellant gas and the normally solid toxicant charge element toaerosolize said toxicant charge when said propellant is fired withoutraising the temperature of a substantial portion of said toxicant to itsdecomposition temperature.

3. A pyrotechnic atomizer especially adapted to aerosolize a toxicanthaving a relatively low decomposition temperature comprising: apyrotechnic gas-generating propellant charge having a relatively lowburning temperature; a toxicant charge comprising a plurality of shapednormally solid charge elements having longitudinal pilot aperturestherein, providing an initial conduit for propellant gases flowingtherethrough, which apertures are enlarged by abrasion of the chargeelements by said gases until essentially the entire charge elements areconsumed; a generally elongate thin-walled casing for said propellantand toxicant charges; a flamefront-limiting partition dividing saideasing into a gas-generating chamber containing said propellant chargeand an atomizing chamber containing said toxicant charge elementsgas-permeably positioned therewithin providing abrading, limitedheat-exchange contact between the propellant gas and the normally solidtoxicant charge elements to aerosolize said toxicant charge when saidpropellant is fired without raising the temperature of a substantialpor-- tion of said toxicant to its decomposition temperature.

4. A pyrotechnic atomizer especially adapted to aerosolize a toxicanthaving a relatively low decomposition temperature comprising: apyrotechnic gas-generating propellant charge; a plurality of toxicantcharge elements having longitudinal pilot apertures therein, providingan initial conduit for propellant gases flowing therethrough, whichapertures are enlarged by abrasion of the charge elements by said gasesuntil essentially the entire charge elements are consumed; a casing forsaid propellant and toxicant charges; a fiamefront-limiting partitiondividing said easing into a gas-generating chamber containing saidpropellant charge and an atomizing chamber containing said toxicantcharges gaspermeably positioned at spaced points therewithin; gas flowdirecting members positioned between said toxicant charges in saidatomizing chamber and adapted to direct propellant gas flowingtherethrough into abrading, limited heat-exchange contact with saidnormally solid toxicant charge elements to aerosolize said toxicantcharges when said propellant is fired without raising the temperature ofa substantial portion of said toxicant to its decomposition temperature.

5. A pyrotechnic atomizer especially adapted to aerosolize toxicantshaving a low thermal decomposition temperature comprising: a pyrotechnicgas-generating propellant charge having a relatively low burningtemperature; a normally solid toxicant charge comprising a plurality ofcharge elements having longitudinal pilot apertures therein, providingan initial conduit for propellant gases flowing therethrough, whichapertures are enlarged by abrasion of the charge elements by said gasesuntil essentially the entire charge elements are consumed; a thin-walledgenerally elongate cylindrical casing for said propellant and toxicantcharges, said casing having one closed end and one releasably sealedend; a flamefrontlimiting partition screen dividing said easing into agasgenerating chamber generally located in the closed end of said casingcontaining said propellant charge and an atomizing chamber generallylocated in the releasably sealed end of said casing containing saidnormally solid toxicant charge elements positioned therewithin toprovide abrading, limited heat-exchange contact between the propellantgas and the toxicant to aerosolize said toxicant charge when saidpropellant is fired without raising the temperature of a substantialportion of said toxicant to its decomposition temperature; an igniterdisposed in heat-exchange relation to said propellant charge; releasablysealing means associated with said releasably sealed end adapted torelease when said propellant is initiated.

6. The method of disseminating a toxicant composition comprisingproviding a relatively high-velocity stream of carrier gases, contactingsaid carrier gas with a normally solid toxicant charge element havinglongitudinal pilot apertures therein, providing an initial conduit forsaid carrier gases flowing therethrough, which apertures are enlarged bythe abrasion of the charge element by said gases until essentially theentire charge element is consumed, said contacting being carried outunder gas velocity conditions providing abrading contact between saidgas and said composition to produce an aerosol of said toxicant in saidcarrier gas, and discharging said resulting aerosol from said atomizingzone.

7. The method of pyrotechnically disseminating a normally solid toxicantcomposition comprising providing a relatively high-velocity stream ofpyrotechnically produced propellant gases; contacting said propellantgases with a normally solid charge element of said toxicant compositionhaving longitudinal pilot apertures therein, providing an initialconduit for propellant gases flowing therethrough, which apertures areenlarged by abrasion of the charge element by said gases untilessentially the entire charge element is consumed, said contacting beingcarried out in an atomizing zone under abrading, limited heat exchangeconditions of pressure, velocity and contact time to produce an aerosolof said toxicant in said gases; and discharging said aerosol from saidatomizing zone.

8. The method of pyrotechnically disseminating an aerosol of a toxicanthaving a relatively low thermal decomposition temperature comprisingigniting a pyrotechnic gas-generating propellant charge in agas-generating zone wherein the flamefront thus produced is physicallysegregated from the toxicant; limiting the path of eX- pansion of thepropellant gases produced in said gas-generating zone to provide arelatively high velocity stream of said gases, directing said highvelocity stream of gases through a normally solid toxicant chargeelement having longitudinal pilot apertures therein, providing aninitial conduit for propellant gases flowing therethrough, whichapertures are enlarged by abrasion of the charge element by said gasesuntil essentially the entire charge element is consumed, said propellantgases contacting said toxicant charge in an atomizing zone underabrading, limited heatexchange conditions of pressure, velocity andcontact time to provide an aerosol of said toxicant in said gaseswithout raising the temperature of a substantial portion of saidtoxicant to its decomposition temperature; and discharging said aerosolfrom said atomizing zone.

References Cited UNITED STATES PATENTS 2,603,607 7/1952 Stevenson 10290X 3,109,821 11/1963 York et al. 102--90X BENJAMIN A. BORCHELT, PrimaryExaminer.

ROBERT F. STAHL, Examiner.

1. A PYROTECHNIC ATOMIZER FOR TOXICANTS COMPRISING: A PYROTECHNICGAS-GENERATING PROPELLANT CHARGE; A NORMALLY SOLID TOXICANT CHARGEELEMENT HAVING LONGITUDINAL PILOT APERTURES THEREIN, PROVIDING ANINITIAL CONDUIT FOR PROPELLANT GASES FLOWING THERETHROUGH, WHICHAPERTURES ARE ENLARGED BY ABRASION OF THE CHARGE ELEMENT BY SAID GASESUNTIL ESSENTIALLY THE ENTIRE CHARGE ELEMENT IS CONSUMED; A CASING FORSAID PROPELLANT AND TOXICANT CHARGES; A FLAMEFRONT-LIMITING PARTITIONDIVIDING SAID CASIGN INTO A GASGENERATING CHAMBER CONTAINING SAIDPROPELLANT CHARGE AND AN ATOMIZING CHAMBER CONTAINING SAID TOXICANTCHARGE